I'm trying to complete an average for time.

The problem is I'm doing this over a 12month period so the months where
there is no data I'm getting the #DIV\0!

in each month i have a time colum at the bottom of each i have a monthly
average colum where i want to get the average time for the month... this is
the formula that i am using:
=IF(AVERAGE(F6:F36)=iserror,"n/a",AVERAGE(F6:F36))

I'm still getting the #DIV\0! error which in turns causes my YTD average to
be the same.

I appreciate your help.